Regarding the method of ammonia vaporization
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Let’s all discuss the methods of ammonia evaporation. I recently visited Jigang and found that they have developed a new method for ammonia steaming, called \"steam-free ammonia steaming\". The basic principle is as follows: By utilizing the principle of distillation, heat transfer oil is used to heat part of the wastewater into steam, thereby evaporating the volatile ammonia present in the remaining ammonia solution and reducing the ammonia content in it. This approach avoids the need to use steam directly for evaporating ammonia. The use of steam has been eliminated, while the amount of ammonia-steaming wastewater generated has been reduced.
This manufacturing process is energy-efficient and reduces wastewater volume; we are preparing to conduct research and carry out modifications!
According to them, it is a completely eco-friendly technology. I asked further at the time, “It’s not about energy conservation, is it?” ”They say, “The concept of pure environmental protection”!
This seems to be a process developed by Tsinghua University, which uses heat transfer oil for heating and distillation in place of a stripping tower; however, it’s not clear what the efficiency of distillation is like. The advantage of a stripping tower lies in its ability to reduce the boiling point of the material by taking into account both temperature and surface partial pressure, thereby enabling the separation of the product. However, heat transfer oil is used for indirect heating, focusing only on raising temperature; therefore, I doubt whether it can provide sufficient heat. One more question: Does the tower that uses heat transfer oil come equipped with a reboiler?
This set of processes has been around for a long time; there are three processes for ammonia vaporization: the direct steam method； Indirect heating method (including steam-heated reboilers and heat-transfer oil-heated reboilers) ； Tube furnace ammonia vaporization method. From an environmental perspective, the direct ammonia vaporization method is the least environmentally friendly, as it also increases wastewater emissions. The indirect method reduces wastewater discharge, but the fixed capital investment for heat transfer oil systems is too high; therefore it is not recommended for small-scale plants (to the best of our knowledge, only Jigang’s coking plant uses this method, while Shougang has prepared interfaces for heat transfer oil reboilers). The cost of indirect steam heating is lower than that of heat transfer oil, but the operating costs are still relatively high. A relatively new method in recent years is ammonia vaporization using a tubular furnace, which neither increases wastewater discharge nor makes full use of the existing gas resources in coking plants. Thereby reducing operating costs and wastewater discharge.
Tianjin Chuangju Technology Co., Ltd. adopted tube furnace ammonia steaming technology at Henan Liyuan Coking Co., Ltd.; the full set of equipment with a capacity of 20 t/h required an investment of around 3–4 million yuan, and it came online in 2008. The gas requirement is approximately 29 m3 per m3 of ammonia water. No steam needed. Tianjin Chuangju Technology Co., Ltd. Contact number: 13312037979; Zhang’s QQ ID: 547598485. Address: East Campus of Hebei University of Technology, No. 8 Guangrong Road, Hongqiao District, Tianjin
It cannot be generalized; instead, the costs need to be calculated by taking into account the local gas and steam prices of the company in question. It should also be noted that heat transfer oil heating is best suited for heating multiple units rather than just one.