Work Package 5: End Use

Leader: University of Oxford

Partners

NTNU, Gasunie, CETH, Naturgas Midt-Nord, DGC
 

Primary Objectives

The objectives of this work package are:

• to develop an inventory of available data on the effect of hydrogen addition and assessment of the impact of hydrogen addition to natural gas on the performance, safety and reliability of current natural gas appliances;

• to carry out trials of a domestic boiler under field conditions using a natural gas/hydrogen mixture;

• to develop membranes for the efficient separation of hydrogen from a hydrogen/natural gas stream and investigate the effect of the changed physical properties of the remaining stream, and the means of re-establishing the gas quality;

• to provide technical options and costs for the separation of hydrogen from natural gas/hydrogen streams to provide pure hydrogen fuelling within the transition period on a widespread basis.
  
  (The transmission and distribution of hydrogen in natural gas networks provides a real opportunity for end users to obtain pure, or nearly pure, hydrogen for a variety of applications, thus helping to create “local hydrogen centres” and enabling the transition towards a hydrogen energy society. To achieve this, low cost and efficient means of separating hydrogen from the natural gas/hydrogen networks must be available. Providing options for hydrogen separation is an important aspect of NATURALHY.)

Current Status of Work Package Activities

Task 5.1: Field test.

A single-family central heated house will be supplied for a period of one year with a mixture of hydrogen and natural gas in order to obtain operational experience and data for ordinary gas appliances.

• Analysis carried out of Wobbe bands for safe operation of the appliances.

• A report is under preparation containing a literature survey of the impact of hydrogen addition in natural gas fired appliances, starting from the European common safety practice in natural gas application.

Task 5.2: Impact on the performance of natural gas appliances from added hydrogen

The impact of adding hydrogen on the performance of NG appliances will be evaluated by analysis of literature data and from information of relevant national projects such as the EET-project “Greening of Gas”.

The laboratory tests preceding the field trials have been successfully completed with encouraging results. The tests are based on the two most popular wall-hung boilers on the Danish market and an older design boiler for comparison.

Task 5.3: Establish targets for hydrogen separation and delivery
 

This task sets specifications and targets for membrane development

A finalised document describing membrane targets and specifications has been produced and agreed by WP5 partners.
 

Task 5.4: Development of high selectivity palladium-based membranes

This work focuses on development of ultra thin palladium-alloy membranes supported on porous ceramic substrates and on model supports to achieve coherent, defect free membranes.

Electroless plating of palladium (Pd) onto a porous alumina substrate has given membranes that meet the 2010 DOE targets for hydrogen flux at 400C. Similar routes to palladium alloyed with silver and copper have not yet produced successful membranes. Manufacturing defects in the ceramic supports have been shown to give rise to pin-hole leaks and mechanical problems. The application of a fine pore (20nm) surface coating smoothes out most substrate defects, but improved substrates are still required.

Task 5.5: Development of new separation membrane materials (carbons, mixed matrix composites).
 

This task investigates carbon based membranes for low temperature (<100C) separation of hydrogen.

Palladium/silver and palladium/copper membranes, varying in thickness between 10 and 40 µm have been prepared and tested for hydrogen permeation and for tolerance to sulphur. Results show that under the same conditions (21 bar and 400°C, using 15% H2/85% CH4) a 20 µm thick membrane works well but hydrogen flux is very low, but as the membrane thickness is reduced, the flux increases. At 20µm thickness, the flux corresponds to 7 kW/m². The target is 50-100 kW /m², which compares well with ECN target for a 3µm thick membrane.

Task 5.6: Development new composite metallic membranes for hydrogen separation

…for new membranes based on a metallic substrate.

High performance Carbon Molecular Sieve (CMS) membranes have been prepared and tested. These materials show high permeability values. Methods of preparation are critical to the performance of the membrane. Pyrolysis in inert atmosphere produces better materials. A parametric study of the effect of final carbonisation temperature, type and amount of metal salt added, carbonisation oven type and atmosphere has been carried out.

Task 5.7: Strategies for preserving gas quality in the pipeline after selective withdrawal of hydrogen.
 

Activities are focused on identifying the needs and evaluation of feasible options for maintaining gas quality

A scenario based approach has been used to determine the most logical options for preserving gas quality, taking into account projected Wobbe limits for EU gases. Three scales of operation have been considered, relevant to the different section of the gas grid.

The three scales are:

• Domestic          5-50 m3/hr (NTP)             @ 1 bar supply

• Intermediate     100-500 m3/hr                  @ 1-8 bar or 8-40 bar supply

• Industrial          700-2000 m3/hr                @ 64-40 or 40-8 bar supply

For each scale, we need to define available separation technologies and the effect of hydrogen concentration in NG.