Natural gas feedstock

As mentioned in Chapter 4, synthesis gas may be produced from a variety of feedstocks. Natural gas is the preferred feedstock when it is available from gas fields (nonassociated gas) or from oil wells (associated gas). 

Methanol production, where CO is added as additive, is very a well-known reaction. The production is carried out in two steps. The first step is to convert the feedstock natural gas into a synthesis gas stream consisting of CO, CO2, H20 and hydrogen. This is usually accomplished by the catalytic reforming of feed gas and steam. The second step is the catalytic synthesis of methanol from the synthesis gas. If an external source of C02 is available, the excess hydrogen can be consumed and converted to additional methanol. 

Petroleum feedstock, natural gas and tar represent the main production chain drivers for the petrochemical industry (Bell, 1990). From these, many important petrochemical intermediates are produced, including ethylene, propylene, butylenes, butadiene, benzene, toluene, and xylene. These essential intermediates are then converted to many other intermediates and final petrochemical products, constructing a complex petrochemical network. Figure 1.4 depicts a portion of the petrochemical alternative routes to produce cellulous acetate. 

FEEDSTOCK NATURAL GAS NAPHTHA HEAVY FUEL OIL COAL (K-T)... 

A high reformer exit temperature of 1616°F is made possible by high alloy tube materials such as Manaurite 36X and Paralloy. This leads to a reduction in methane slip, and an increase in the CO/CO ratio. Both effects enhance the plant s efficiency and result in a reduction of feedstock natural gas consumption of 3.5% over previously used reforming conditions. 

Description The feedstock (natural gas as an example) is desulfurized, mixed with steam and converted into synthesis gas over nickel catalyst at approximately 40 bar and 800°C to 850°C in the primary reformer. The Uhde steam reformer is a top-fired reformer with tubes made of centrifugal high alloy steel and a proprietary "cold outlet manifold" system, which enhances reliability. 

Description The feedstock (natural gas as an example) is desulfurized, mixed with steam and converted into synthesis gas over nickel... 

Feedstock Natural Gas Liquefied Waste Vacuum Residue Liquefied Co... 

As an example of the use of a purge stream, consider the production of NH3. Steam reforming, with feedstock natural gas, LPG, or naphtha, is the most widely accepted process for ammonia manufacture. The route includes four major chemical steps ... 

Synthetic gas can be produced from a variety of feedstocks. Natural gas is the preferred feedstock when it is available from gas fields (nonassociated gas) or from oil wells (associated gas). The first step in the production of synthesis gas is to treat natural gas to remove hydrogen sulfide. The purified gas is then mixed with steam and introduced to the first reactor (primary reformer). The reactor is constructed from vertical stainless steel tubes lined in a refractory furnace. The steam to natural gas ratio is 4—5 depending on natural gas composition (natural gas may contain ethane and heavier hydrocarbons) and the pressure used. A promoted nickel-type catalyst contained in the reactor tubes is used at temperature and pressure ranges of 700 800°C and 30—50 atm, respectively. The product gas from the primary reformer is a mixture of H2, CO, C02, unreacted CH4, and steam. The main reforming reactions are ... 

Ammonia is the principal component in the fertilizer production. The world ammonia capacity for 1995-1996 is estimated at 123,640,000 tons of nitrogen per year [70], Ammonia plants are high energy consumers, and selection of the feedstocks is the most important factor in determining the capital investment and production costs. The availability and cost of raw materials are factors to be taken into account when deciding on the construction of a new ammonia plant. The primary feedstocks for ammonia production include natural gas, naphtha, heavy residual oil, coke gas, and coal. Of all these feedstocks, natural gas is the raw material of choice when available because it ensures minimum investment and production costs, a plant that is easy to operate, and minimal environmental problems. Therefore, steam reforming of natural gas has become the most widespread process for ammonia production. 

The future outlook for ethylene prices depends heavily on feedstocks. Natural gas liquids—primarily ethane/propane—constitute about... 

Canadian methanol production, especially the two plants located in the Province of Alberta, were in very serious financial difficulty in the mid-1980s. The cost of the feedstock natural gas was not considered a value comparable to that of other remote-area producers, and it is ejq)ensive to ship this methanol to deep-water export facilities, located in Kitimat and Vancouver in British Columbia. Attempts were made to ship methanol via a products pipeline from Edmonton, Alberta to Vancouver and also via a liquefied petroleum gas pipeline from Edmonton to Chicago and Windsor, Ontario, but these tests proved only marginally successful and the methanol that was received was off-specification and suitable basically only for fuel uses. The two Alberta methanol producers, Novacor and Celanese Canada, reduced their total costs by renegotiating feedstock gas contracts and shipping rates both to Canadian ejq)ort ports and directly to the United States. 

---