I.

Executive Summary and Introduction

1

II.

Technical Overview

4

III.

Stoichiometric and Thermodynamic Constraints

20

A.

Devolatilization

20

B.

Gasification Reactions

20

IV.

Indirect Heating of the Gasifiers

37

V.

Computation of Thermal Efficiency

38

VI.

Effect of Equilibrium and Kinetic Constraints on Steam Requirements of Gasifiers

39

VII.

Effect of Steam-to-Oxygen Ratio on the Performance of the Simplified Gasifier

43

VIII.

Methane Formation

53

IX.

Countercurrent Feed of Coal

67

X.

Methane Reforming and Direct Injection of Coal into a Hugh Temp. Reaction Zone

79

XI.

The Effects of Coal Properties on Gasifier Design

87

XII.

Pressure Effects

97

XIII.

Temperature Constraints

101

XIV.

Real Gasifiers

102

A.

Two-Stage Entrained Bed Gasifier (Modified BiGas)

105

B.

Gasifiers with a Separate Air Combustor

105

C.

Differential Evaluation of Gasifiers

110

1.

The BCG-Lurgi Moving Bed Slagging Gasifier

110

2.

Texaco Gasifier

119

3.

Fluid Bed Gasifiers

127

XV.

The Use of External Shift with Low Hydrogen to Carbon Monoxide Ratio Gasifiers

134

XVI.

Summary, Conclusions and Recommendations

137

XVII.

References Cited

140