Hydrogen Production from Hydrocarbon Based Fuels via thermo chemical Methods

Hydrogen
Hydrogen is a synthetic fuel with various and plentiful feedstocks for synthesis. Water, coal and natural gas may be considered first among these feedstocks. Hydrogen has the highest energy content per unit weight among all known fuels (120,000 kJ/kg). It covers only 1/700 of its gas phase volume when converted to liquid hydrogen. Only steam and heat is formed when it is combusted with pure oxygen. Although nitrogen oxides are formed when it is combusted with air, hydrogen causes less pollution compared to other fuels. Taking all of these into account, hydrogen may be considered as one of the important secondary energy source alternatives.

Today, an average of 50 million tones of hydrogen is produced annually for technological needs. Applications of hydrogen is listed below;

Catalytic Hydrogenation
Solidification of vegetable oils
Synthetic fabrics production
Medicine production
Ammonia synthesis
Methanol synthesis
Alcohol production from fatty acids
Metal hydride preparation
As a fuel

in rockets
Electric generation

in metallurgy

Reduction material
Tungsten and molybdenum production

Hydrogen is produced from water and fossil fuels like natural gas, petroleum products and coal. 48% of hydrogen produced worldwide is obtained from natural gas because of its high hydrogen content, relative cheapness, cleanliness, adequate network infrastructure and large reserves.
Studies on hydrogen production from hydrocarbon fuels (especially natural gas and diesel) via thermo chemical methods are carried out in the Energy Institute.

Hydrogen Production via thermo chemical Methods
thermo chemical methods for hydrogen production consists of auto thermal reforming, partial oxidation and steam reforming Of existing hydrocarbon fuel sources.
In steam reforming, steam and fuel is reacted endothermically to form hydrogen and carbon monoxide. Also, water-gas shift reaction takes place in parallel to that reaction. These two reactions take place over supported nickel catalyst at temperatures above 500°C.
In partial oxidation, fuel is reacted with substoichiometric oxygen. Partial oxidation of methane takes place at 1200-1300°C. The reaction can take place at lower temperatures if a suitable catalyst is used. The reaction is exothermic and the heat generated should be removed and used effectively.
auto thermal reforming can be considered as the combination of steam reforming and partial oxidation. Suitable amounts of natural gas, steam and air (or oxygen) are fed to the reactors and a hydrogen-rich gas mixture is obtained eventually. In auto thermal reforming, endothermic and exothermic reactions take place together and thus, there is no need to remove or add heat to the system.
The hydrogen-rich gas mixture obtained from all these systems also contains some amunts of carbon dioxide, methane, steam, carbon monoxide and sulphur. In order to be able to feed the hydrogen-rich gas to low-temperature fuel cells, carbon monoxide and sulphur should be removed from the gas mixture. For this purpose, hydrogen purification systems (water-gas shift reactors, preferential oxidation reactors, pressure swing adsorption beds and sulphur adsorption beds) are used.

Activities of the Energy Institute

modelling & Design
Design, manufacture and tests of hydrogen production systems from hydrocarbon based fuels can be carried out at the Energy Institute.
Hydrogen production system consists of a reformer reactor in which a hydrogen-rich gas are produced from primary fuels and hydrogen purification reactors in which carbon monoxide, sulphur and other impurities are removed from the hydrogen-rich gas. Block diagram of a hydrogen production system are depicted below in Figure 1.

For process design studies, simulation of hydrogen production system is carried out in a chemical process simulation program. For the steady-state and dynamic simulations of chemical processes, ASPEN Plus, ASPEN HYSYS, HYSYS Dynamics and MATLAB are used in the Institute. The interface of the simulation of hydrogen production system carried out by ASPEN HYSYS is shown in Figure 2.

modelling studies using Computational Fluid Dynamics (CFD) for the critical components are one of the significant topics of interest at the Institute. Effects of the design on flow inside the component, temperature distribution, conversion and efficiency are investigated with CFD modelling studies. FLUENT software is used for this purpose in the Institute. Within the scope of a Project, the effect of the gas feed unit design on gas composition was investigated with CFD modelling (Figure 3).

Lab scale test & Analysis
There are two experiment systems in Tubitak MRC Energy Institute which can be used for reactor/catalyst test tasks in laboratory scale. In these systems gas mixtures with desired composition, flow rate, temperature and pressure can be prepared and used for determined reaction tests shown in Picture 1.

Fabrication & Assembly

There is a considerable background about manufacture and montage of the chemical processes, especially hydrogen production systems. A mechanical workshop is operating in the institute to manufacture reactors and other components. In the mechanical workshop, there are lathes, milling machines etc.Some of the fabricated reforming reactors and setups are shown in Picture 2..

In the scope of an international Project entitled MCFC_NAV , a fuel processing system, production system producing hydrogen rich gas from diesel oil has been built in the institute. The capacity of the fuel processing system is about 450Nm3/h hydrogen + CO. A picture of the system can be seen at Picture 3.

Hydrogen Demonstration Park

HYDEPARK project (2005-2008) was submitted to the State Planning Organization of Turkey (DPT) for the national project call in 2005. The project had been started on 1st of June 2005. The management of all work packages is carried out in the leadership of TUBITAK Marmara Research Center Energy Institute and with the support of the collaborator organizations.

The main goal of this national project entitled "Development of Hydrogen Production, Conversion and Storage Technologies (HYDEPARK)", is to research hydrogen technologies and renewable energy applications. Design and development of a standalone renewable hydrogen production and storage system are being investigated. The project has two segments of the laboratory studies such as indoor and outdoor applications. Indoor reactor systems with the required sub-units are designed and assembled for hydrogen production from natural gas. The outdoor installations of the plant consist of 145 PV panels (~ 12 kWp), wind turbine (5 kWp), PEM type electrolyser (1.05 Nm3/h, max 13.8 bar.), a diaphragm type hydrogen compressor (1.5 Nm3/h, 100 bar) with the required sub-units for hydrogen production/pressurization and hydrogen storage units which have metal hydride & compressed cylinders. All these system components will be integrated with a 2.4 kWp PEM fuel cell system to obtain electrical energy by using the hydrogen as a fuel. The project is in the demonstration phase.

1. Introduction

Hydrocarbon fuel sources like natural gas and cost-effective renewables are the main near-term sources for the hydrogen transition while, in the longer run, more mature renewables will play an important and ultimately a dominant role. The short-term aim in Europe should be to increase supply from renewable energy sources on the continent but, in longer term, renewable energy sources will become the most important source for the production of hydrogen. The hydrogen technologies of primary interest include renewable sources (PV, Wind etc.), biomass gasification and electrolysis with related purification technologies (such as gas cleaning, pressure swing adsorption, separation by palladium membranes, etc.). Currently, the reforming of natural gas is the most economical process for producing hydrogen. Within decades, hydrogen produced from biomass, wind and solar sources will be the ultimate, abundant, renewable based energy currency.
Although hydrogen-related technologies are at a respectable level of maturity in European Union (EU) countries, research in this area is not widely developed in Turkey as a Candidate Country (CC) of the EU. This proposed project is designed to improve the existing research capacities of the Center in order to bring future projects to an elevated level of maturity and sophistication. Such improvement in the Center's research capacity, in combination with improved networking, will promote enhanced participation on international platforms, including 7th Framework Programme, and ultimately promote renewable hydrogen technology advancement on a global scale.
Producing hydrogen by processing hydrocarbons or by electrolysis using electricity from fossil fuels releases large amounts of carbon dioxide. However "well to wheels" comparisons of using hydrogen as a fuel take into account all such greenhouse gas emissions and hydrogen still comes out on top. When hydrogen is produced from renewable hydrocarbons, such as biomass, or by using electricity from renewable energy sources, such as wind power, the carbon dioxide emissions will be very less.
Hydrogen, in many respects, is much better as a fuel than existing transportation fuels. Hydrogen possesses a very high flame speed and a wide range of flammability limit. A hydrogen-fuelled vehicle is intrinsically devoid of problems such as vapor lock, cold wall quenching, inadequate vaporization and improper mixing. All of these problems are very closely related to the characteristics of conventional fuels such as gasoline and diesel, and they do not occur in a hydrogen-powered vehicle. In the long term, hydrogen could play a key role in adapting energy supply to energy demand as hydrogen has the potential for large-scale, even seasonal, energy storage.
For both transport and stationary applications, widespread and affordable production and a reliable hydrogen distribution system should be in place. The outlook for future markets for hydrogen as a fuel can be seen to be governing by two economic scenarios: (1) hydrogen produced from fossil sources, and (2) hydrogen produced from nonfossil sources. While not currently practical, it appears that nonfossil energy sources will become dominant in the future. Considerable progress has been made in the search for alternative energy sources since the oil crisis of 1973. A long-sought goal of energy research has been a method to produce hydrogen fuel economically by using nonfossil fuels such as sunlight, wind and hydropower as the primary energy source. Although production of hydrogen via the use of solar cells or wind has been regarded as the cleanest and most desirable method, these processes do not supply enough hydrogen at the present stage.

2. GENERAL DESCRIPTION OF PROJECT

2.1 Overview

HYDEPARK "Hydrogen Demonstration Park" (2005-2008) is one of the parts of our national State Planning Organization (SPO) project. Project proposal was submitted to the State Planning Organization of Turkey (DPT) for the national project call in 2005. The project was funded by SPO and it had been started on 1st of June 2005. The main goal of this national project entitled "Development of Hydrogen Production, Conversion and Storage Technologies (HYDEPARK)" is to research on hydrogen technologies and renewable energy applications. Design and development of a standalone renewable hydrogen production and storage system are being investigated.
The project has two segments of the laboratory studies such as indoor and outdoor applications.

The reactor systems with the required sub-units for hydrogen production,
PVs, wind turbine and an electrolyser (PEM type) with the required sub-units for hydrogen production by using renewable energy sources.

Integration of these systems will be carried out with PEM fuel cell system to obtain energy by using the hydrogen as a fuel, which is generated and stored. HYDEPARK Project demonstrates the integration of renewable energy and hydrogen production for several applications.
The design & installations have already been working in TUBITAK Marmara Research Center Energy Institute. Most of the components have been installed on site.

There are several units in this demo plant such as;
Small scale wind turbine (5 kWp)
PV modules (~ 12 kW) , 145 modules (CIS thin film, multicrystalline and monocrystalline modules).
Electrolyser PEM type, 1.05 Nm3/h.
Hydrogen compressor, Diaphram, 1.5 Nm3/h.
Hydrogen storage (in MCPs and MH tanks)
PEM fuel cells with control units.(for residential and transport applications)

There is also a small scale NG fuel reformer installation on-site in the laboratory for hydrogen production.

2.2 System description

A demonstration wind & PV powered hydrogen production plant has been designed, procured, and constructed, and preliminary single component tests have been performed. All the applications, tests and the technological studies will be performed in 2007. Back-up studies, aimed at determining the tolerance of conventional PEM electrolyzer to input power fluctuations and the potential for smoothing the output from wind & PV power generators, will be carried out in parallel. In all cases, experimental results will be backed up by theoretical analysis and computer simulation, resulting in models of component and system operation at various levels of detail. Description of components and the demo plant are given in Figure 4 and Picture 4.