Hydrogen production from biomass is gaining more attention due to the depletion of fossil fuel sources. Tea waste as an agricultural waste is a promising feedstock in order to obtain hydrogen-rich gas via gasification.

Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means "water-former".

Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is problematic in metallurgy because it can embrittle many metals, complicating the design of pipelines and storage tanks.

The application of hydrogen is vast as one of it uses is involved in generation of electricity. Electricity can be generated via combining hydrogen and oxygen atoms. Another major use of hydrogen gas during modern days revolves around automobiles as hydrogen is widely utilized in hydrogen fuel cells for high efficiency and zero emission electric vehicles. Moreover, hydrogen is widely used in production of carbon steels as well as carrier gas in gas chromatography.

In production of fertilizer, hydrogen is combined with nitrogen in forming ammonia before the ammonia compound is converted into nitric acid via catalytic oxidation. Hydrogen is used in reduction of iron ore such as separation of oxygen from iron ore using hydrogen and synthesis gas.

The tea waste usually ends up disposed as municipal waste however it can be recycled and reused for greater use such as production of biogas, bio-oil and biochar and producer gas hence a process flow of production hydrogen gas from tea waste is proposed via gasification process.

There are several methods in synthesizing hydrogen gas including thermochemical methods such as pyrolysis, combustion as well as gasification as well as biochemical method such as extraction and hydrolysis.

The advantage of synthesizing hydrogen via gasification of biomass is to serve as alternative to replace methane gas which is originated from petroleum hence application of biomass despite of petroleum is a more environmental-friendly option as this substitution helps mitigating the drilling of earth crust as well as protecting marine life.

The raw material for our process is tea waste. Tea waste can be obtained by two main ways which can be classified as outside Malaysia and inside Malaysia. Outside Malaysia means to import tea waste from major tea producing companies such as India and Sri Lanka. The Figure below shows the countries which have imported tea wastes from India. We can see Malaysia with a percentage less than one percent while other countries like Vietnam and Indonesia which are also ASEAN members have percentage way higher than that of Malaysia. This is because Malaysians are still unaware of the benefit and reusability of the tea wastes unlike other countries. Inside Malaysia on the other hand, to get the tea wastes locally, we can start buying tea wastes from restaurants, hotels and so on since many tea wastes are produced here. Upon considering both options, it was decided that obtaining them from overseas is much easier as it is less of a hassle and the price is also affordable.

The process to produce hydrogen from tea waste feedstock has five major unit operations named as Dryer, Gasification unit (Fluidized Bed Gasifier), Tar Reformer (Reactor), Water Gas Shift Reactor, and Pressure Swing Adsorption Unit.

• Dryer: the spent tea leave contains moisture that must be dried to a specific moisture content before being fed to the gasifier unit. The moisture content must in the range of 30-15%.

• Gasification unit (Fluidized Bed Gasifier): after the spent tea waste was dried the biomass feedstock must be heated under combustion condition in the fluidized bed gasifier. Steam and oxygen are fed to the gasifier and distributed in at the bottom of the hot bed. The tea leaves will be heated up and syngas will be coming out at the top while ash will the residual at the bottom. Syngas will contain carbon monoxide and hydrogen.

• Tar Reformer (Reactor): the syngas comes from the gasifier enter the tar former as the syngas will contain inorganic and organic impurities and particles. Methane and tars are produced. Tars are high molecular weight inorganic compounds that must be removed, or it will contaminate downstream equipment’s and inhibit fuel synthesis. One way of removing tar is by adding a special catalyst to compounds into additional syngas.

• Water Gas Shift Reactor: In the Water Gas Shift, Carbon monoxide will be converted to hydrogen and carbon dioxide by reacting with steam. The reaction is reversible, and the unit does not include change in the volume where it is only used to increase the conversion of hydrogen. The reaction will be carried out in high and low temperatures in order to achieve the specific yield.

• Pressure Swing Adsorption Unit: PSA removes virtually any gas phase impurity to the specified level. PSA increases the separation and the purity of the hydrogen gas. The hydrogen purity in the PSA can be up to 99.99%.