How to calculate the steam consumption for anti-freezing in winter for air coolers used to cool oils with high viscosity

Many years ago, I reviewed the anti-condensation design for the wax oil air cooler at Daqing Refining School; it wasn’t actually that complicated. First, you need to determine the temperature at which freezing and blockages occur in that area during winter. For example, in Daqing, this happens when the temperature drops below around -15°C; at such temperatures, ordinary air coolers will stop their fans from operating. If the temperature is even lower, operation in insulated mode is required. Generally, air coolers are equipped with louvers whose angles can be adjusted; when operating in insulated mode, hot air is needed, which means steam is used for heating in this case. Specifically for heat load calculation, you can determine the steam consumption by taking the wax oil outlet temperature and adding 10 to 20°C to it, based on the annual average atmospheric temperature. For example, at the average annual atmospheric temperature, when your air cooler is operating normally and the temperature of the wax oil exiting the air cooler is 65°C, then for anti-condensation design purposes, you can use this temperature along with values between 75°C and 90°C to calculate the heat load. I recall it being 30 tons per hour of paraffin oil, with a heat load of around 600,000 to 700,000 kcal/h; if an electric heater is used, the theoretical power would be approximately 800 kW, which is quite high. When performing calculations, pay attention to the specific heat data of paraffin oil; different qualities of paraffin oil have considerable differences in their specific heat Cp, with the largest difference I’ve encountered being 20%. Sufficient margin should be reserved in the heat load design, with a recommendation of no less than 30%. Anyway, the steam flow rate can be adjusted. The best way is to use other oils that need to be cooled to heat the air, and add a fan to create a circulation of hot air; this is much more energy-efficient than using steam. . In Daqing, with this type of hot air circulation, the system operates in heat-retaining mode for roughly 30 days per year, about a month.

Thanks for going to the trouble, buddy. In other words, under normal conditions the wax oil temperature drops from 200ºC to 65ºC; this load is denoted as Q1. When calculating, we assume that the wax oil temperature drops from 200ºC to 75–90ºC, and this load is denoted as Q2. So, Q1 – Q2 represents the load that my steam needs to provide?

The calculation is correct, but your approach is really strange. . . :Lol, just do the calculation directly: Q = WCpΔT. For example, with wax oil at 30 t/h, using Cp value of 0.6 and a temperature difference of 25°C, we get Q = 30,000 x 0.6 x 25 = 450,000 kcal/h, which is equivalent to 523 kW. Considering a 30% safety margin, the value becomes 700 kW. . .

Haha, I originally wanted to change the exit temperature in HTRI and run a simulation to get two values for heat load; subtracting those two values would be sufficient