Shifting demand and problems with production, inflation, low productivity and energy will place growing strains on the world economy in the 1980s, according to a study by The Conference Board.

"The world economy has become increasingly interdependent, and there is no longer the expectation that a strong impulse somewhere among the economies of the developing countries might compensate in part for slow growth in the industrial world," the study says. It was prepared for a conference sponsored by the board, a nonprofit, nonpartisan business research organization, and SRI International.

The U.S. Export-Import Bank yesterday approved its first two loans to the Peoples Republic of China since the Carter administration promised such activity.

The bank said its directors agreed to lend China a total of $57.1 million at yearly interest of 8 3/4 percent to purchase power plant equipment and technology from Westinghouse Electric Corp. and Combustion Engineering Inc.

The bank, which makes loans to encourage trade between the United States and other countries, had approved a "preliminary commitment" for the two loans last February, and President Reagan had determined that they would bee in the national interest.

The dollar continued to advance against all major currencies yesterday in a rally that began late Tuesday on signals that U.S. interest rates will remain firm.

Gold declined in Zurich to $456.50 an ounce from $461.50 on Tuesday, and in London to $455.50 from $464.25. It eased in New York to $456.75 from $461. The New York Commodity Exchange settled gold at $456.50, down from $461.50. Silver fell to $9.92 an ounce from $10.20 and settled on the Comex at $9.96, down from $10.23.

The pound fell in London to $1.8240 from $1.8320 and in New York to $1.8040. London dealers said the pound's weakness reflected firmer Eurodollar rates and anticipation that the U.S. budget deficit will keep U.S. dollar interest rates high.