Gasification – Application Overview

Gasification – Application OverviewEcoPack® Product Focus

Gasification is a thermal/chemical process that converts any carbon-containing material into a synthesis gas composed primarily of carbon monoxide and hydrogen. During this process, a lower-value carbonaceous/hydrocarbon feedstock (coal, petroleum coke, biomass, etc.) is subjected to high temperatures, moderate pressures and reducing conditions, for conversion to a higher value synthesis gas (syngas) by means of partial oxidation with air, oxygen, and/or steam.

The hydrogen-to-carbon ratio of coal is lower than that of liquid or gaseous fuels. Therefore conversion of coal into an alternative fuel must involve either an addition of hydrogen or a rejection of carbon.

Gasification converts low value residuals into higher value synthetic products. Petroleum feed is mixed at high temperatures (above 350°C/662°F) with oxygen and steam in a gasifier vessel. A hydrogen and carbon monoxide gas mixture called synthesis gas (syngas) fuel is produced and drawn from the gasifier.

The syngas is further scrubbed and cleaned. An inter ash/slag by-product is also produced at the bottom of the gasifier.

PROCESS BENEFITS: 

Fuel flexible

  • Coal, pet coke, refinery wastes, biomass, sewage sludge and MSW
  • High sulfur feeds accepted

Environmentally superior

  • Low CO, SOx and NOx emissions
  • Zero particulate emissions
  • No solid wastes
  • Sulfur recovered as by-product

PROCESS: 

  • A hydrocarbon feedstock is fed into a high-pressure, high-temperature chemical reactor (gasifier) containing steam and a limited amount of oxygen.
  • Under these ‘reducing’ conditions, the chemical bonds in the feedstock are severed by the extreme heat and pressure and a syngas is formed and drawn from the gasifier.
  • The moisture in the feedstock is evaporated and exits the gasifier in the vapor phase as a component of the gas stream, acting as a diluent, thereby reducing the energy content of the gas.
  • Under the reducing conditions in the gasifier, most of the fuel’s sulfur converts to hydrogen sulfide (H2S).
  • The syngas is further scrubbed/cleaned.
  • An inert ash/slag by-product is also produced at the bottom of the gasifier.

MARKET APPLICATIONS: 

  • Refinery based co-production (power, steam, hydrogen) from coke, resid.
  • Baseload power
  • Coal repowering
  • Combined cycle refueling
  • Feed to chemicals – NH3/urea
  • Feed to methanol
  • Feed to ultra-clean fuel (diesel)

DRIVERS: 

  • Electric power deregulation
  • Increased energy demand
  • Clean energy solutions – greenhouse gas reductions
  • Strain on natural gas – driving prices up – supply uncertainty
  • Continued reliance on coal in U.S.
  • Significant reserves – clean coal emphasis
  • Significant world scale coking capacity additions – more pet coke on the market
  • Refineries processing heavier crudes – results in lower value pet coke
  • Increased demand for hydrogen in refineries
  • Ultra clean transportation fuel
  • Direct reduced iron production
  • Chemicals – ammonia / fertilizers

ENVIRONMENTAL BENEFITS:

  • Gasification processes “bad actors” in coal/coke prior to end use
  • Allows power generation of low value fuels (feeds) with near natural gas performance and emissions
  • Lower all around emissions versus conventional solid fuel technologies

SUMMARY: 

  • Gasification is the cleanest, most efficient commercial means to generate power from solid fuels
  • Continuing trend of oil, gas and electric power markets improves IGCC prospects
  • Growth rate of gasification is accelerating – additional opportunities in chemicals (from coal and petcoke)
  • Environmental pressures (including Hg, CO2) favor gasification
  • Technical advancements aid gasification
  • Challenge – providing the market a mature technology
  • This industry represents a ripe market for specialty valve OEMs due to combination of technology, plant size and market growth
DIFFERENTIATING FEATURES
Integral seat – safety of isolation

  • It is inherently impossible for the seat to disassociate from the valve body under any operating condition
Highest spring strength in the category

  • Spring strength inhibits ball movement
  • Maintains positive seating under various pressure differentials and Is a necessity for zero leakage and longevity
  • The spring strength is made evident by the two-piece body configuration; the body must be mechanically torqued to close due to the compression strength of the spring. It is not feasible to have high spring strength with top loaded or end loaded valve internals.
Coatings/seating surface

  • RiTech® coating is applied precisely and has high bond strength
  • ValvTechnologies is the only known ball valve manufacturer to bring their coating process in house and under robotic control.

 

FLOW DIAGRAM
Item Applications Temp range (°F) Pressure (psi) Size (in)
1 Slurry tank emergency block valve 250 – 500 100 – 200 6 – 10
2 Feed slurry pump isolation 38 – 100 100 – 200 6 – 10
3 Gasifier isolation 38 – 150 900 – 1200 6 – 10
4 Oxygen feed isolation 38 – 100 900 – 1200 4 – 8
5 Coarse slag lock hopper isolation 50 – 350 900 – 1200 6 – 12
6 Lock hopper drum inlet 200 – 320 900 – 1200 12 – 24
7 Lock hopper drum outlet 200 – 320 900 – 1200 12 – 24
8 Level control let down isolation 38 – 150 100 – 200 4 – 10
9 Backwater flash drum isolation 50 – 350 900 – 1200 4 – 10
10 Oxygen depressurizing valve 38 – 100 900 – 1200 4 – 8
11 Oxygen depressurizing isolation 38 – 100 900 – 1200– 2600 4 – 8