DeNora cells

The DeNora cells [68,72] have cathode areas ranging from 4.5 to 36 m, operating at 10-11 kA m . These cells are covered with a flexible, multilayer sheet of an elastomer, which is supported by the anode rods. DSA anodes, with four stems per anode, are suspended in frames supported from the cells. 

Encouraging laboratory experiments since 1994 with oxygen-depolarised cathodes (ODC) in chlor-alkali as well as hydrochloric acid electrolysis motivated the development of this technique up to the industrial scale. Based on the predictions of the theory, the reduction of cell voltage could be expected up to 1 V (Fig. 4.1) for both applications. Early on, the proper choice and improvement of ODC, deriving mainly from the DeNora group, led to results with voltages as predicted in short tests as well as in endurance tests conducted over dozens of months at the Bayer endurance test facilities. 

For HCI electrolysis the cathodic reaction product is water, which is easily drained through the ODC without affecting the membrane water content. Consequently, the ODC can be attached directly to the membrane and pressure compensation is not necessary. The cell concept, which was developed in another co-operation with DeNora, could not be simpler - the basic cell principle is shown in Fig. 4.6. Initial laboratory tests conducted in 1994 at Bayer on the basis of old GE developments [4] demonstrated the feasibility of HCI electrolysis with ODC and the potential for a reduction of the cell voltage to about one-third of present values. 

Balko, E.N. (1979) SPE hydrochloric acid electrolysis cells performances. Cell Configuration, Oronzio DeNora Symposium - Chlorine Technology. See United States Patent No. 4,311,568 and United States Patent No. 4,294,671. 

Gruppa DeNora NUVERA FUEL CELLS INC GT Solar (Shanghai) Co., Ltd GT SOLAR INTERNATIONAL INC... 

During the 1960s, major research efforts were devoted to the oxides of platinum group metal exhibiting high metallic conductivity, and in 1967, Beer invented RuO2 coatings on Ti substrates for application as anode in chlor-alkali cells.40 41 These dimension-ally stable anodes (DSA ) have been further developed and commercialized by V. deNora.42... 

These systems were mostly non-pressurized bipolar electrolyzers produced by Bamag, Norsk Hydro, BBC/DEMAG and DeNora, whose outputs amounted to approximately 300 Nm h hydrogen. Rectangular (Fig. 11.5) and circular electrodes and cells with an active electrode area of up to approximately 3 m were used. 

PPG and DeNora jointly developed a bipolar filter-press diaphragm cell called the Glanor electrolyzer [32]. The central design feature is the bipolar electrode where one side acts as an anode and the other as a cathode. The electrode consists of a steel plate to which anode fingers are connected on one side and cathode fingers on the other. 

W.B. Darlington, Activated Cathodes for Reduced Power Consumption in Electrolytic Cells, In O. DeNora (ed.). Proceedings of the DeNora Symposium on Chlorine Technology., Venice, (1979), p. 30. E. Nicholas, Fr. Appl. 7917441(1979). 

Presently, there are five mercury-cell technologies [70,71] practiced in the world, and their operating characteristics are summarized in Table 5.2. The only technology supplier that is active in optimizing the cell design and the cell operations to achieve negligible mercury emissions is DeNora [72]. 

The cells are equipped for automatic anode adjustment in groups, by electric motors, with short-circuit protection. The anodes are not individually adjustable in the support frames. Flexible copper straps to the anode bus bars connect the anode rods individually, and the cathode current is carried by a cathode plate and copper bus bars. Figure 5.8 is a cross-sectional view of the DeNora mercury cell. 

FIGURE 5.8. Cross section of the DeNora mercury cell [71]. (a) Cell base (steel) (b) Side wall (rubber-lined steel) (c) Lifting gear (d) Transverse support (e) Lengthwise support (f) Anode carrier (g) Anode rod (h) Anode surface (i) Adjustment motor (k) Bus bar G) Flexible anode current strap (m) Multilayer cell cover (n) Service walkway (o) Intercell bus bar (p) Switch (q) Insulator (r) Switch drive (s) Support. (With permission from John Wiley Sons, Inc.)... 

DeNora also developed a new anode design, called the Runner anode, with the THM (Titanium Hydrodynamic Means) configuration (Fig. 5.11) which utilized the gas lifting force to improve mixing of the brine, thereby eliminating the concentration gradient of brine from the bulk to the mercury interface. This allowed the operation of the cells at the... 

D. Francis, DeNora s Cell Room Technology Enhancements to Reduce Mercury Emissions, paper produced at the Chlorine Institute Conference, New Orleans (2001). 

G. Oliva, The Return of DeNora to Diaphragm Cell Technology with Glanor . In Proceedings, Oronzio de Nora Symposium on Chlorine Technology, Venice (1979), p. 279. 

DeNora Permelec S.p.A. has developed an electrolyzer (trade name Hydrina) with such an anode [104,105]. The first application has been the production of NaOH from Na2C03. The cell has three compartments, separated by a cation-exchange membrane on the cathode side and a porous diaphragm on the anode side (Fig. 15.19). The hydrogen generated at the cathode goes to the depolarized anode. Water is fed to the cathode... 

Most recently, nickel cathodes with activated, or so-called electro-catalytic, coatings have been developed for use in membrane cells by Dow, DeNora, Oxytech and others. These developments superbly complete the metamorphosis of the chlor-alkali cell from its crude beginnings with its mediocre... 

DeNora DN 350 Bipolar Electrolyzer. The DeNora DN 350 bipolar electrolyzers (Fig. 61) is of the filter-press type. The frames are very large (3.5 m ) and are compressed by mechanical screw jacks to ensure proper tightness. The electrolyzer can be operated with a slight overpressure. Anolyte and catholyte are recirculated in the cell by baffle plates and special downcomers. Fresh brine and diluted caustic soda are fed to the bottom section of each compartment. Anolyte with CI2 and catholyte with H2 leave the elements through insert pipes at the bottom of the cell. The electric current flows from the anode to the cathode surface through an array of welded electrical connectors of highly conductive metals (e.g., steel or copper). These connectors are interposed between the titanium anode wall and the nickel cathode wall, to which they are welded. The cathode walls are cold pressed to create a pattern of bulges. 

DeNora D88/DI75 Monopolar Electrolyzer. Monopolar electrolyzers with two different areas (0.88 and 1.75 m ) are available. The DD-type monopolar electrolyzer (Fig. 62) is a self contained unit assembled on a separate base structure and fitted with an integrated gas - liquid system. The anodic and cathodic cell frames are compressed like a filter press with rubber gaskets and a tie-rod system. The current is conducted to... 

Nuvera fuel cells Cambridge, MA PEM Residential, transportation N/A Several automotive customers DeNora Fuel Cells (Italy), Epyx Corp. (A.D. Little), Amerada Hess... 

Locomotives—Propulsion Research Institute started a consortium that demonstrated a fuel cell-powered locomotive for mining operations (the fuel cell was built by DeNora). 

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