The last step in the production of milk powder is drying, an energy intensive process that demands 30% to 40% of the total energy input of a typical plant. It takes place in Spray Dryers (SD), where concentrated milk is sprayed and placed in direct contact with hot and dry air that cools down and gains humidity as water is evaporated from milk. The warm and humid air leaving the SD contains a small portion of potentially recoverable sensible heat and a large portion of latent heat that is impractical to recover by direct condensation due to the low dew point of this stream and due to the presence of milk powder particles that become sticky at high relative humidity values. In this research, the
thermodynamic feasibility of a liquid sorption system for the recovery of heat from the exhaust of SD’s was investigated. The system proposed has two main advantages: the dehumidification of air in the absorber for reuse in the SD, and the production of medium pressure steam in the regenerator for integration to the steam network of the plant. A mathematical model was implemented in Matlab, and two system configurations were evaluated. The calculations showed that a SD equipped with this system can achieve energy savings between 58% and 99% when using aqueous solutions of phosphoric acid as liquid desiccant depending on the system configuration. The challenge with this liquid desiccant remains on the construction materials.@en

The last step in the production of milk powder is drying, an energy intensive process that demands 30% to 40% of the total energy input of a typical plant. It takes place in Spray Dryers (SD), where concentrated milk is sprayed and placed in direct contact with hot and dry air that cools down and gains humidity as water is evaporated from milk. The warm and humid air leaving the SD contains a small portion of potentially recoverable sensible heat and a large portion of latent heat that is impractical to recover by direct condensation due to the low dew point of this stream and due to the presence of milk powder particles that become sticky at high relative humidity values. In this research, the thermodynamic feasibility of a liquid sorption system for the recovery of heat from the exhaust of SD’s was investigated. The system proposed has two main advantages: the dehumidification of air in the absorber for reuse in the SD, and the production of medium pressure steam in the regenerator for integration to the steam network of the plant. A mathematical model was implemented in Matlab, and two system configurations were evaluated. The calculations showed that a SD equipped with this system can achieve energy savings between 58% and 99% when using aqueous solutions of phosphoric acid as liquid desiccant depending on the system configuration. The challenge with this liquid desiccant remains on the construction materials.@en

The recovery of cold energy during the regasification of Liquefied Natural Gas (LNG) has gained attention in recent years due to the fast growth of the LNG trade market and the increasing importance that governments are giving to energy efficiency and sustainability. Near 200 kWh/ton of LNG are potentially recoverable during the regasification process, but this energy is usually discarded when seawater or ambient air are used as heat source. Researchers have focused on the development of technologies for the use of this cold energy in the fields of air separation and cryogenic power generation. However, in some regasification plants the demand of natural gas is so low or so fluctuating that this kind of applications are economically unfeasible. This research focused on determining the techno-economic feasibility of a heat pump and a cold distribution system for the transfer of a fraction of the refrigeration capacity of LNG to industrial assets with low-temperature refrigeration demands located in the surroundings of the regasification plant. CO2 was selected as the heat transfer fluid that recirculates in a close loop between the cold users and the LNG site. A techno-economic model was implemented in Matlab taking the distance between the users and the LNG plant, and the refrigeration demand as the evaluation parameters. It was found that for a refrigeration demand of 20 MW the distance between the plants should be less than 1.2 km in order to make a project economically feasible.@en