Pakistan is facing a serious energy supply difficulties due to rapid increase in demand, poor endowment of energy resources, high costs of energy imports, expanding industrialization and high population growth. Being an agricultural country, biomass can be a potential solution for this energy shortfall. However, undesirable properties like high moisture content, slagging nature, low heating value, higher power consumption for grindability, low heating value, low carbon and hydrogen content etc. are big barriers for its commercial utilization. Various biomass pretreatment solutions have been proposed to improve the properties of raw biomass. Among different pretreatment processes, demineralization and torrefaction are viable options. Torrefaction, a thermal pretreatment process, is defined as the mild pyrolysis of lignocellulosic material in temperature ranges of 200-300 ^oC. While demineralization is the reduction in content of alkali and alkaline earth metals in biomass to lessen its slagging nature. The thermochemical effect of torrefaction and demineralization on the biomass has been studied. The focus is on determining the influence of leaching agents and leaching time on the physiochemical structure of rice husk during demineralization. It is observed that H₂SO₄ exhibited higher removal of alkali and alkaline earth metals (AAEM). The acid has been seen to induce more notable changes in physiochemical structure as depicted by the FTIR spectra and SEM micrographs. The thermal degradation behavior of the demineralized rice husk has also been reported. Finally torrefaction reactor has been described.