Development of Ammoniated Salts Thermochemical Energy Storage Systems. Phase I, Task 3: Salt Kinetics. Topical Report

摘要

This program is for the development of an energy storage system that accepts thermal energy at high temperatures, stores it at near ambient temperature, and recovers the energy on demand at a temperature near the original high temperature. The energy is stored as both sensible heat and chemical energy. The system is completely passive, having no moving parts, and can be used over a wide range of source temperatures. The concept consists of the storage and subsequent abstraction of heats of reaction from a pair of ammoniated chemical systems near equilibrium. By shifting the equilibrium in the forward or reverse direction, the heat of reaction in stored and recovered as desired. This energy storage system could have a role in providing peaking energy to a peaking turbine, for residential energy storage, and to store and recover waste heat from an industrial complex. The end objective of the work is to demonstrate the concept's applicability to power plant thermal storage systems. To this end a three-phase program is planned. The objectives of Phase I, Task III were to determine the kinetics of the dissociation and recombination of 10 candidate ammoniated salts, (calcium, ferrous, and magnesium salts) and to determine the effects of cycling, impurities, moisture and particle size on the kinetics. Heats of reaction for each of the salts were measured. All of the calcium chloride ammoniates reacted both reversibly and reproducibly. A large volume expansion accompanied the formation of all of the salts when ammoniates were formed from the anhydrous salts. This large volume change eliminated any effects of original particle size (100 to 400 mesh). Reproducible rates of reaction could not be obtained with FeCl sub 2 salt from 3 different sources, nor with the Mg Cl sub 2 salts obtained from two different sources. Anhydrous magnesium chloride prepared in the laboratory gave completely reversible, reproducible results in much the same manner as the calcium salts. (ERA citation 06:030492)