The 7 th Taiwan-Thailand Bilateral Conference Kiln improvement for rock salt production Rujapa Nanthapodej, Samruad Inban 1 Engineering Program Nakhon Phanom University 103 Moo 3 Chayangkol Road, Tambol Khamtao A.Muang, Nakhon Phanom Thailand 48000 Abstract In Northeast Thailand, rock salt was produced by boiling method. Among of 57 in 147 house- holds earn their living by rock salt harvesting, mostly by boiling method using a local de- signed kiln. Most expenditure in this method was energy cost, such as firewood and fuel for water pump. During the conservative forest law, log wood was limited and expensive. There- fore, applying rice husk as alternative energy sources for kiln was introduced in this study. Three kiln models were built as Type1, Type2 and Type3. The performance of these models was compared against the local designed kiln. The result showed that the Type3 model, de- signed with two combustion chambers was the best kiln for rock salt production. 1. Introduction Mineral resources such as rock salt (geologically, “halite”) is generally found in the North- Eastern of Thailand. Rock salt is used extensively in cooking as a flavour enhancer and to cure a wide variety of foods. Firstly, Rock salt was produced by collecting white crust of salt from soil surface and put them to a container. The container comes with many holes at the bottom. While water is poured to this container, water will dissolve the salt into the water, and leak out through holes at the bottom of container. After boiling the salt-water solution, salt will precipitate out when the water temperature reach 60-70 degrees Celsius. Nevertheless, in commercial productions, salty un- derground water will be pumped up and boiled on kilns. This study aimed at improving kiln for salt production. The main activities were the design, construction, testing the kiln, and the analysis of rock salt harvesting method to improve kiln’s competency and productivity. Heat lost in combustion chamber was concerned in ex- periments. In addition, utilizing rice husk as alternative energy sources was also taken into account to solve the shortage of firewood problem. 1 Corresponding author: samruad_inban@npu.ac.th