The production of bio-based chemicals and fuel from biomass is considered cleaner production technology for environmental protection. In the present study, establishing a new process to convert biomass to highly pure sugars and solid biofuel by concentrated acid hydrolysis was investigated. The sugar production process was based on two-steps concentrated H2SO4 hydrolysis of rice straw followed by separation and purification of sugars. Moreover, ethanol was separated from acids by using a distillation unit. The hydrolyzer unit can convert 10 kg/h rice straw to sugars, and their final yield was 1 kg sugars per batch. An economic method for separation of sugars by precipitation using ethanol and highly efficient acid recovery (90 %) and ethanol (95-98%) was achieved without using resins. High-performance liquid chromatography analysis for hydrolysate revealed that it contains 77% xylose, which can be used as natural diet sugars. The production of 70 -100 kg natural diet sugars and 700 kg solid biofuel (Calorific value of 6952 kJ/kg) were obtained from 1000 kg rice straw. The results from the pilot plant could be considered as a step towards the commercialization of the process.