Liquid ammonia evaporator

First, determine the type of evaporator: 1. Assuming a structure similar to a kettle-type reboiler, where liquid ammonia is present in the kettle with some space for evaporation, and the cold medium flows inside the tubes, calculation is performed using the KETTLE type of HTFS ； 2. Assuming it is a liquid ammonia container plus an external heater, similar to a reboiler in distillation, it can be calculated using the HTFS thermosyphon reboiler ； Liquid ammonia evaporation is also used for heat transfer in reaction vessels; there are various configurations, so we’ll talk about that later. For reference only.

Is the heating medium circulating water, steam, or waste heat? Our company specializes in the production of ammonia evaporators, which feature full automatic control and are simple yet reliable. Contact: http://www.nh3.com.cn, Mr. Liu, 18917378778

What the poster is referring to is the evaporator used for cooling; there are traditional shell-and-tube heat exchangers available. One can consult companies such as Wuhan New Century, Yantai Binglun, and Dalian Bingshan directly. These are series-produced products, and there is mature experience in terms of calculation. Currently, plate heat exchangers are the standard choice for use as evaporators. You can explain your requirements to GEA Shanghai or Alfa Laval; these companies have established calculation methods, and they can provide information on the available equipment models and prices. Without performing the calculations manually, companies that specialize in manufacturing such equipment will arrive at more accurate results.

Who makes liquid ammonia evaporators? More communication? Evaporator process calculation?

Hello, I would like to calculate the heat transfer coefficient for using liquid ammonia for heat removal in a reactor. Are there any models or empirical formulas that I can refer to?

This post was last edited by DXJ122 on 2014-9-11 at 19:07. Liquid ammonia is used for heat transfer in reaction vessels; it’s not possible to specify the exact value of the heat transfer coefficient here. But note two aspects: 1. Assume that liquid ammonia evaporates inside the coiled tubes located within the reactor; in this case, refer to the α calculation methods applicable to coiled tubes. 2. For the calculation of α for the reactants inside the reactor, first of all, it depends on the properties of the materials (properties related to heat transfer), and secondly, it involves the structure and size of the reactor, as well as the type, structure, size, and rotation speed of the agitator. . . . With these 2 issues resolved, the others, such as the thermal resistance on both sides, become a bit easier. Note: α is a Greek letter, pronounced alpha.

Are the empirical formulas for coiled tubes and jackets the same? The formula I found gives a heat transfer coefficient on the liquid ammonia side of 130,000 W/(m2·K); this seems too high, so the formula must be incorrect. Do you have any reference materials on this topic, such as articles or books?

There are at least two types of coiled tubes: one type is coiled in a spiral shape, resembling a spring, while the other type consists of vertical tubes. In one variant, three tubes form a group, and there are usually 6 to 8 such groups; circular rings at the top and bottom connect to these tubes. As for the heat transfer coefficient α based on experience, I am used to working with the unit KCAL/M2 HR ℃, and it’s a quite high value; from memory, it’s around 5000 to 10000. You can calculate the unit conversion by yourself. The heat transfer coefficient α for evaporation is very high, but the controlling factor is the heat transfer coefficient α of the material inside the reactor. The evaporation heat transfer coefficient α of the jacket has not been used by me. But it should be quite large too. It’s difficult to discuss coiled tubes since they cannot be represented graphically.

Could you provide more specific calculation methods? For example, if the flow rate of liquid ammonia is 60 KG/h, what size heat exchange area is required?

Could you provide more specific calculation methods? For example, if the flow rate of liquid ammonia is 600 KG/h, what size heat exchange area is required?